Occupational Lung Disease
Pulmonary and Critical Care Medicine · Occupational Lung Disease 🎯 Practice these cards
MKSAP Table 21 organizes the occupational exposure history into four domains: occupation; type and extent of ____; the ____ relationship of symptoms to work; and other relevant exposures such as hobbies and pets.
MKSAP organizes the occupational screening interview into four domains (Table 21): (1) Occupation — current duties, tenure, changes over time, and a full accounting of all prior jobs; (2) Type and extent of exposure — work-area description (size, ventilation, visible dust), vapors/gases/dusts/fumes, respiratory protection use, and access to Safety Data Sheets; (3) Temporal relationship to work — symptoms after a process change, improvement away from work, similarly affected coworkers; (4) Other relevant exposures — hobbies (woodworking, auto restoration), pet birds, residential history, and travel. Because latency ranges from hours (byssinosis) to decades (asbestosis, mesothelioma), the history must capture the entire working life, not just the current job.
The ____ details an agent's chemical properties and known health risks; under ____ regulations, workers have a right to obtain it from their employer.
When occupational lung disease is suspected, request the Safety Data Sheet (SDS) for each relevant agent from the employer; it details chemical properties and known health risks. Under U.S. OSHA regulations, workers have a right to this information, and employers must provide it along with training in protective equipment and exposure control. Because process changes may alter exposures that only line workers recognize, a site visit — or a worker-requested OSHA inspection — can be informative; current measurements combined with the job history allow reconstruction of past doses.
The cornerstone of management for virtually every occupational lung disease is ____ of the offending agent; an index case is considered a ____ event that should trigger workplace investigation of coworkers.
For virtually every occupational lung disease, the key intervention is removing the causative agent from the workplace — or removing the worker from the agent. An index case is a sentinel event: coworkers with the same exposure can be identified, treated, and protected. Disease-specific care then proceeds as for the non-occupational counterpart (e.g., glucocorticoids for severe occupational hypersensitivity pneumonitis or asthma), but without exposure cessation, medical therapy alone will fail.
____ silicosis appears after 15–20 years with upper-lobe rounded opacities and 'eggshell' hilar calcification (up to 20%), whereas ____ silicosis develops after only months of intense exposure as a pulmonary alveolar proteinosis–like syndrome with 'crazy paving' on HRCT.
Silicosis forms are keyed to exposure intensity and tempo: (1) Chronic simple silicosis — the common form, with small rounded upper-lobe opacities after 15–20 years of lower-intensity exposure; 'eggshell' hilar lymph node calcification occurs in up to 20% of cases. (2) Complicated silicosis/PMF — nodules coalesce into irregular masses >1 cm, typically upper lobes, with mixed restrictive–obstructive impairment; nodular fibrosis can progress even after exposure stops. (3) Accelerated silicosis — the same picture compressed into ~5–10 years by heavier exposure. (4) Acute silicosis — after only months of intense exposure (confined-space sandblasting, tunneling, engineered-stone fabrication), a pulmonary alveolar proteinosis–like syndrome with diffuse ground-glass opacification and 'crazy paving' on HRCT; rapidly progressive and potentially fatal; whole-lung lavage may palliate.
In Australia's engineered-stone screening program (Hoy, Lancet Respir Med 2025), ____% of 1,003 screened workers had silicosis and ____% already had PMF, supporting ____-based screening in this workforce.
Australia's national screening program evaluated 1,003 workers (mostly engineered-stone fabricators; median age 37 years, median exposure 8 years): 33% had silicosis and 10% already had PMF, with an overall CT prevalence of 42%. Radiologic disease tracked cumulative exposure rather than tenure — 46% of silicosis cases had under 10 years of exposure — and HRCT detected disease missed on plain radiographs, supporting CT-based screening in this workforce. PMF has appeared after as little as 2 years of fabrication work, and disease can progress despite removal from exposure.
OSHA's permissible exposure limit for respirable crystalline silica is ____ µg/m³ as an 8-hour time-weighted average, with an action level of ____ µg/m³.
OSHA's respirable crystalline silica standard (consolidated in 2025 compliance guidance) sets a permissible exposure limit (PEL) of 50 µg/m³ as an 8-hour time-weighted average, with an action level of 25 µg/m³. Construction employers may follow the specified exposure-control methods of Table 1 in lieu of air monitoring. Mandatory medical surveillance includes spirometry and chest radiography every 3 years for workers exposed above the action level for 30 or more days per year, along with respiratory-protection requirements — the regulatory backbone for catching silicosis before PMF develops.
NIOSH surveillance documents a resurgence of coal workers' pneumoconiosis, especially ____, concentrated in central ____ and linked to mining thinner, higher-rank seams that generate more respirable crystalline ____ dust.
Simple CWP — small rounded opacities after 15–20 years at the coal face — is seen in roughly 10% of all coal miners and in up to half of anthracite miners with >20 years of exposure. Complicated CWP (nodules ≥1 cm, generally in the upper half of the lungs) can progress to PMF with severe functional deficit; crystalline silica within mine dust is thought to drive much of the PMF risk. After decades of decline following federal dust standards, NIOSH surveillance documents a resurgence of CWP — especially PMF — among U.S. coal miners, concentrated in central Appalachia and linked to mining of thinner, higher-rank coal seams that generate more respirable crystalline silica dust.
The more pathogenic asbestos fibers are the ____ (e.g., crocidolite, amosite) rather than serpentine chrysotile; asbestosis typically has a latency exceeding ____ years and produces ____-lobe predominant linear opacities, while pleural ____ mark exposure but not impairment.
Asbestos comprises serpentine (chrysotile) and the more pathogenic amphiboles (crocidolite, amosite, anthophyllite, tremolite, actinolite). Asbestosis is a diffuse interstitial fibrosis directly related to exposure intensity and duration, with latency from exposure to clinical disease typically exceeding 25 years. The radiographic hallmark is irregular, linear opacities beginning in the lower lung fields; HRCT shows characteristic subpleural curvilinear lines parallel to the pleura. PFTs reveal restriction with reduced DLCO. Pleural plaques — parietal pleural thickening/calcification over the lower fields, diaphragm, and cardiac border — mark exposure, not impairment, and should trigger assessment for asbestosis, benign asbestos pleural effusion, diffuse pleural thickening, and malignancy.
Asbestos-related lung cancer risk interacts ____ with cigarette smoking, whereas mesothelioma is ____ associated with smoking; more than ____% of mesotheliomas are attributable to asbestos.
Asbestos causes two distinct malignancies. Lung cancer is the more common (all histologic types; minimum latency 15–19 years) and its risk interacts multiplicatively with cigarette smoking — the combined risk exceeds the sum of individual risks. Mesothelioma (pleural and peritoneal; ~3,000 U.S. cases/year) is rarer but far more specific: more than 80% of mesotheliomas are attributable to asbestos, making a documented mesothelioma in an exposed worker presumptively compensable. Mesothelioma is NOT associated with smoking and can follow brief exposures of 1–2 years occurring up to 40 years earlier, so household and bystander contact must be queried.
In IARC Monographs Vol. 136 (2025), all commercial asbestos forms were reaffirmed as Group ____ carcinogens, with the evidence for ____ cancer upgraded to 'sufficient' alongside mesothelioma, lung, and stomach cancer.
In Monographs Volume 136 (2025), IARC re-evaluated all commercial asbestos forms (chrysotile, crocidolite, amosite, anthophyllite, tremolite, actinolite) and reaffirmed them as Group 1 carcinogens with sufficient evidence for mesothelioma and cancers of the lung, ovary, and stomach — upgrading the evidence for ovarian cancer to 'sufficient' — with limited evidence noted for laryngeal cancer. The evaluation underpins the WHO's continuing push toward global elimination of asbestos use.
Chronic beryllium disease mimics ____ and is screened with the ____ test; confirmation requires transbronchial biopsy showing ____ granulomas in a sensitized worker (e.g., aerospace or nuclear industry).
Beryllium — a lightweight, high-strength metal used in aerospace, automotive, nuclear, telecommunications, and electronics industries — causes a chronic granulomatous disease clinically, radiographically, and histologically indistinguishable from sarcoidosis (except that hilar adenopathy is somewhat less common). The screening test of choice is the beryllium lymphocyte proliferation test (BeLPT), which demonstrates a specific cell-mediated (delayed-type hypersensitivity) response to beryllium salts; diagnosis then requires bronchoscopy with transbronchial biopsy showing noncaseating granulomas in a sensitized patient. Susceptibility is strongly linked to HLA-DP alleles carrying glutamic acid at position 69 of the β chain. Embedded shrapnel in combat veterans can also be a beryllium source.
Hard-metal (tungsten carbide) lung disease causes giant cell interstitial pneumonia, attributed to its ____ binder, whereas ____ exposure has been linked to pulmonary alveolar proteinosis.
Tungsten carbide ('hard metal') — encountered in tool and die work, saw blade and drill bit manufacture, and diamond polishing — causes giant cell interstitial pneumonia, with its cobalt binder the likely culprit; cobalt also causes occupational asthma. Indium exposure has been linked to pulmonary alveolar proteinosis. Aluminum and titanium dioxide have rarely produced sarcoid-like granulomatous reactions. Practical rule: any patient with interstitial lung disease should be asked specifically about metal fumes and dusts; surgical (VATS) lung biopsy is reserved for puzzling presentations such as giant cell interstitial pneumonia from cobalt.
Byssinosis results from ____ dust exposure in textile workers; its hallmark is chest tightness and falling FEV1 on the first day back at work ('____ chest tightness'), and OSHA mandates pre- and post-shift ____ surveillance.
Workers exposed to cotton dust (also flax, hemp, and jute) in textile and rope manufacture develop an asthma-like syndrome linked to both dust and endotoxin levels. The hallmark is chest tightness toward the end of the first day back at work — 'Monday chest tightness' — with a measurable fall in FEV1 across the Monday shift; early on, symptoms do not recur later in the week. With continued exposure symptoms may persist, and after more than a decade an obstructive pattern can become fixed. OSHA requires pre- and post-shift spirometric surveillance in cotton-dust workers, and any worker with persistent symptoms or falling function should be moved to a lower-exposure area.
Sensitizer-induced occupational asthma requires a ____ period; ____ (RADS) is irritant-induced asthma with no latency after a single overwhelming exposure; occupational factors account for ____% of the adult asthma and COPD burden; and management requires strict ____ cessation.
Sensitizer-induced occupational asthma follows a latency period of sensitization to high-molecular-weight proteins (flour in bakers, laboratory animal dander, latex) or low-molecular-weight chemicals (diisocyanates, acid anhydrides, aromatic amines — which do not necessarily operate through IgE). Reactive airways dysfunction syndrome (RADS) is irritant-induced asthma WITHOUT any latency period, arising after a single overwhelming exposure to a corrosive gas, vapor, or aerosol. Occupational COPD is under-recognized: dusts and fumes (coal, grain, cotton, cadmium, welding fumes) cause chronic bronchitis and fixed airflow limitation even in never-smokers, with effects additive to smoking; small-airway inflammation is the initial lesion. Overall, occupational factors account for 15–20% of the adult asthma and COPD burden, and management of all forms requires strict exposure cessation.
Farmer's lung, the prototype occupational hypersensitivity pneumonitis, is caused by ____ spores in moldy hay; acute attacks begin ____ hours after exposure with fever, cough, and dyspnea without ____, mimicking influenza.
Farmer's lung — from thermophilic actinomycete spores in moldy hay — is the prototype of occupational hypersensitivity pneumonitis. Acute attacks begin 4–8 hours after exposure with fever, chills, malaise, cough, and dyspnea without wheezing, closely mimicking influenza or pneumonia; repeated attacks can evolve into patchy fibrosis that must be distinguished from sarcoidosis and other fibrotic interstitial lung diseases. Many other agents (malt, mushrooms, bird droppings, isocyanates, acid anhydrides) cause the same syndrome, and IgG precipitins (e.g., avian antigen in bird handlers) support the diagnosis. Occupational HP often cannot be controlled without complete cessation of the causative exposure.
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